The recent incidents of anthrax-laced letters being transported through the United States Postal Service (USPS) facilities to unsuspecting recipients has alarmed the nation and the world. Currently, the tainted letters are discovered after the recipient accepts delivery or by alert postal employees noticing white powder that could be anthrax on mail parcels or pieces, sorting and distribution equipment, or themselves. There appears to be no current security devices or procedures that are available to intercept such letters at the earliest source of introduction into the USPS system, for example at the mailbox or post office drop box or mail collection tub, or upon entry into a sorting facility or sorting system to test them for hazardous material, and to neutralize such material when it is found.
Currently when there is suspicious mail, it is all bulk irradiated as was done during the recent anthrax problem thereby delaying some mail for months and damaging or destroying some of the mail due to problems caused by the irradiation. For example some of this irradiated mail became brittle and pieces broke off.
Almost all mail articles at one time or another are collected and transported to postal facilities by way of mail tubs. Therefore, mail tubs can be the first point of containment if a hazardous material is detected prior to the exposure of its air and contents at a postal facility.
Mail is also distributed in large trucks such as tractor/trailers, and this provides another opportunity to detect hazardous material on or in the mail.
Some mail tubs have lids or covers, but they are not airtight vessels. Mail articles that contain hazardous material within or on the outer surface contaminate not only the other mail articles within the mail collection tub, but also the mail collection tub air. The agitation of the mail collection tub in transport or by routine handling by the postal employees can cause the hazardous material to form a plume or aerosol. There is also a threat of contaminating postal employees by inhaling the contaminated air as well as by direct contact to skin tissue.